Copper wire

We had a problem with our solar water heating system. With so many dull days we turned it back to the winter heating so that it was on the relay to heat up at night but a cool shower two mornings running had us ringing the electrician. He got up into the roof cavity where the cylinder is and reported that there was a leak onto the thermostat and replaced it with a new one. These are some snips of wire he left lying around in the garage.
Next was the plumber who said it may mean a new cylinder but he will investigate whether there is some other way to stop the leak. It is all original so well over 20 years old. Can't complain. I don't envy whoever has to get up in the roof cavity in this heat.
We did get a tap fixed and a down pipe as well so that was something.